Fluid flow measuring apparatus



Jan- 21, 1947- L. CROSBY ETAL FLUID FLOW MEASURING APPARATUS Filed Feb. 26, 1944 INVENTUES 6 Sheets-Sheet 1 YM m NW A n w N m L Jan. 21, 1947. L. E. CRQSBY ETAL FLUID FLOW MEASURING APPARATUS- Filed Feb. 26, 1944 6 Sheets-Sheet 2 CHAELEJ a? \M TJPA UTMAN 4 ATNRNEY Jan. 21, 1947; E. CROSBY EI'AL FLUID FLOW MEASURING APPARATUS Filed Feb. 26, 1944 6 Sheets-Sheet 3 v m'vsufaxs LAWEE'NCE E. Czaaar gmmss w TEAUTMAN 4 -AT727ENEY Jan. 21, 1947. E. CROSBY ETAL 2,414,582

FLUID FLOW MEASURING APPARATUS Filed Feb. 26, 1944 6 Sheets-Sheet 4 mama's LAWRQENCE 5; cm CHARLES ,w 17mm d ArmzusY Jan-21,1941. L. E. CROSBY Em 2,414,582

FLUID FLOW MEASURING APPARATUS Filed Feb. 26, 1944 6 Sheets-Sheet 6 Fig.5

llwwraes LAWRENCE E. czasav BYQ/AELES \M T?AU7'MAN 4 8 I I I AT'MENEY Patented Jan. 21, 1947' 2414,582 FLUID FLOW MEASURING APPARATUS Lawrence Eacrosby and Charles W. Trautman, South Bend, Ind., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application February 26, 1944, Serial No. 529,994 17 Claims. to]. 73-3) This invention relates to carburetor flow box systems and particularly to automatic means. for correlating various scales of pressure differential or the like with various sized orifice openings or combinations of orifice openings through which fluid in such a fiow box system is passed.

It is well known to use flow boxes to make various tests for carburetors. Some of such flow boxes include an air bottle having removable air orifices and an inclined manometer having various scales for use in connection therewith, different scales being used with respective orifices or combinations of orifices. In. such devices each scale is calibrated to measure the flow through the pressure drop across an orifice or combination of orifices of certain capacity and said scales are 2 so graduated and arranged that the readings on said scales overlap. For example, one scale is adapted to register such drop up to the full throat opening or capacity of the orifice orcombinations of orifices.

Since the amount of fiuid, such for example as air, supplied to a charge forming device or carburetor for internal combustion engines or the like varies between wide limits, depending upon the demands of the internal combustion engine, it is desirable to have a device which is adaptable to all conditions of demand, and which will throughout the range of demand furnish an accurate measurement of the air supp1y.- It is obvious that a single size orifice is not readily adaptable to all conditions of fiuid flow. That is, an orifice small enough to produce at low flows a differential pressure sufiicient in amount to be accurately measured will be too small to accommodate the high rates of air flow and conversely, the use of an orifice sufficiently large to accommo date large air demands will give almost no measurable difference in pressures across the orifice 7 under conditions of low air demand. For this reason it is advantageous to provide a plurality of orifices of different sizes, each particularly used for say a small orifice which will read up to the full throat opening thereof, and another scale is used for the next larger orifice and provides a reading up to the full throat opening of the latter orifice with a portion of said scale reading on the full throat opening of the smaller orifice. Thus a continuity of readings can be accurately made throughout the range of orifice sizes or capacities.

Heretofore orifice insets of various sizes have been used but such insets have been changed by hand, the appropriate scale on the inclinometer then being independently brought into position for indicating the air flow, the tube of said inclinometer being filled with a suitable liquid as is well known in the art. The scalesfit may be noted are mounted on a rotatable support or drum and as the support is rotated the respective scales are moved into a position with respect to the manometertube whereat the height of the liquid in said tubemay be easily measured or read on the respective scale.

With such an arrangement there is always the danger of inadvertently using the wrong scale in connectionwith the orifice which is being used in a test so that the results of the test will be erroneous. In addition considerable time and labor is involved in changing the orifices by hand as said orifices may be quite large and heavy.

It is therefore an important object of the present invention to provide means for the elimination or such errors in the correlation of the manometer scale with the orifice being used and it is a more particular object of the invention to antomatically correlate the scales of the manometer or the like with the orifices or combinations adapted to measure the fiow through a particular portion of the range. stances it is also desirable to provide air through a plurality of orifices. A desirable feature, therefore, in such a multiple orifice fiow meter lies in the ability to quickly change the size of orifices desired for particular air demand and to change the pressure differential gauge or scale used therewith with comparative, ease and rapidity, each gauge or scale being calibrated for its corresponding orifice to indicate directly the rate of air flow or pressure difierential across said orifice. Where a plurality of scales and a plurality of orifices or combinations thereof or various capacities are used it is desirable to have the scales Under some circumof orifices being used in a test.

Another object of the invention is to provide means for automatically rendering various orifices'eifective as a scale is changed and. it is a further object of the invention to provide control means whereby the respective orifice or group of orifices are automatically rendered operative as each scale is brought into position with respect to the manometer tube.

Still another object of the invention is to provide a plurality of fixed orifices which are controlled by respective valves and wherein one or more orifice air valves may be actuated to open respective orifices as respective scales are moved into position adjacent the manometer tube.

A further object of the invention is to provide a device of this character wherein a plurality of cept for size, so that a description of only one of said valve members will be given herein. Each The invention still further contemplates that g the electrical system be controlled by the scale mechanism and said electrical system in turn controls various air valves of the pneumatic system whereby air under superatmospheric pressure actuates the orifice air valves.

Other objects of the invention will be apparent from a study of the description and accompanying drawings and it is to be understood that the scope of the invention is not limited to the embodiment shown, which is for the purpose of illustration only, nor otherwise than by the terms of the appended claims.

In the drawings which are employed merely for the purpose of illustrating a preferred embodiment of the invention;

Figure 1 is a side view, of a flow box embodying the present invention;

Figure 2 is a view of the rear of same;

Figure 3 is a plan view of the same;

Figure 4 is a front view of the flow box control panel;

Figure 5 is an enlarged view of the air bottle of the fiow box taken on line 5--5 of Figure 1;

Figure 6 is an enlarged sectional view of one of the air orifice insets and the control valve therefor taken on line 6--6 of Figure 5;

Figure '7 is an enlarged schematic longitudinal section of an air control valve in the pneumatic control system;

Figure 8 is an enlarged schematiclongitudinal section of a solenoid operated air control valve of the pneumatic control system, the pneumatic control valve and orifice valve operating means being included in this view;

Figure 9 is a schematic view of the pneumatic and electrical systems; and

Figure 10 is an enlarged section taken on line l0l0 of Figure 4.

Referring more particularly to Figure 1,-there is shown an air box I!) having an air inlet. con nection 12 with an air bottle l4. The air box 10 is provided with a manifold l6 through which air is withdrawn from said box I ll by any well known means such as a suction pump or the like, said manifold having a connection at 18 with the bottom of the air box, a branch 20 connected with the top of the box, and a branch 22vconnected with one side of the box. These various connections provide convenient means for testing various types of carburetors such as the updraft type, the downdraft type, or the horizontal delivery type, as is well known in the art. A door 24 is provided for the box to permit access thereto.

Air enters the upper end of the bottle I4 through one or more valve controlled orifice insets, best shown in Figure 6. As the insets are all substantially alike except for size only one will be described. Each inset comprises a flange 26 from which a tubular portion 28 depends through an opening 30 in an orifice plate 32 which forms the upper end wall of the air bottle l4. Screws 34 secure the flange 26 to the plate 32 and a gasket 36, of any suitable material, is provided to prevent leakage of air between the parts. It is to be noted that the throat of the orifice is flared inwardly at 38 from the outer end of the inset similarly to a venturio The movable-valve members for the reof said valve members comprises a valve plate 40 having a sealing gasket 42, which may be leather or other suitable material, secured thereto as hereinafter described, to insure effective sealing of the orifice opening by the valve member, it being understood that the upper face of the flange 26 serves as a-valve seat for the movable valve member or closure and said seat and movable valve member are to be considered herein as the orifice valve. A ball and socket joint connects the-valve plate and gasket 42 with a shaft 44, said joint comprising a recessed member 45 having a depending portion 46 of reduced diameter which extends through the plate 40 and gasket 42 and has a nut 41 threaded onto the free end thereof,

said nut securing the member 45, plate 40 and gasket 42 together. The member 45 is externally threaded and is screwed into a member 48 and a ball 49 is received in the recess of member 45 and is provided with an integral stem 50 which is horizontal cross members 5Ib, provides support ing means for the orifice valve members, pneumatic motors 52 which actuate said valves and pneumatic control valves 53 controlling the air to the motors 52, there being a motor and neumatic control valve for each orifice valve. Each motor 52 comprises a cylinder 54, Figures 1 and 8, and a piston 56 slidable therein, said piston 56 being connected with the shaft 44 of the respective movable orifice member and said piston is adapted to' be actuated by air pressure for opening and closing said orifice valve. Each motor 52 is connected with the respective valve 53 by air connections 58 and 60 which communicate with the lower and upper ends respectively of the cylinder 54 so that air under pressure may be admitted to either end of said cylinder according to the position of the control plunger of the valve 53, hereinafter described, such air under pressure being understood to mean herein air under such superatmospheric pressure as to be capable of actuating the various pneumatic devices of the present invention. i Each pneumatic valve 53, best shown in Figure 7-, comprises a cylinder 64 having a control plunger 66 slidable therein. The cylinder has an inlet 68 adapted to be connected with a conduit or pipe 10 which in turn is connected,by

means of a pipe H, Figure 9, to a source'of air under pressure shown herein at 12 as a pressure tank, said tank being supplied with air under pressure by a suitable air compressor of any, well known type, not shown. However, the compressor may be directly connected withthe valves 53 or any-other suitable arrangement may be employed to provide air under pressure for the pneumatic system. The air inlet 68 of the valve 53 is located intermediate the ends of the cylinder 64 and is adapted to register, and communicate, with a passage 16, or a passage 18 respectively in the plunger 66 in accordance with the position of said plunger. The plunger is urged to the position shown in Figure 7 by a spring which is disposed about a reduced diameter portion 82 of the plunger adjacent one end thereof and reacts between a shoulder 83 r of the plunger and a wall member 84 screwed into the adjacent end of the cylinder 64, the-plunger being limited in its movement to the right by the 1 7 6 with conduit 96 and the chamber 94 is cut ofi irom communication with the conduit 60.

Air under pressure to the chamber 86, transmitted by conduit 85, is controlled by a solenoid valve indicated generally at I50 and best shown in Figure 8. Said valve comprises a hollow casing member I52 with which conduit 85 is conthe conduit 60 so that air under pressure is supplied to the upper end of the cylinder 64 to actuate the piston 56 in the downward direction for urging the orifice valve member against the seat or flange 26 and thereby closing the orifice. In order to efiect upward movement of the piston 56 for opening of the orifice valve, air under pressure is admitted through a pipe 85, connected to a solenoid controlled valve hereinafter described, into 'a chamber 86 of the cylinder 64, the outer end of said chamber 86 comprising the rigid wall orhead 81 and the inner wall of said chamber 86 being a flexible diaphragm 88 connected to a reduced diameter extension 90 of the plunger 66. The extension 90 is provided with a shoulder 9| from which a threaded end portion extends and is received in an opening in the diaphragm adjacent the center thereof. Reinforcing washers '92 are provided on each side of the diaphragm and said washers and diaphragm are clamped securely between the shoulder BI and a nut 93 on said threaded portion. Air under pressure in the chamber 86 is adapted to urge the diaphragm 88 to the left,

as viewed in Figure 7, and force the plunger 66 to the left until the reduced diameter portion 82 engages the wall 84 which limits said movement of the plunger. When the plunger is in its extreme position to the left the opening 68 is in registry with the transverse portion of passage 18. The air under pressure is then transmitted from passage 16 and port 66 through passage 18 and conduit 58 to the lower end of the cylinder so that the piston 56 is moved upwardly.

When the plunger 66 is in the last mentioned position and the piston 56 is moved upwardly,.

air in the upper part of the cylinder 5-9 must be exhausted to permit such upward movement of J the piston 56 and said air is exhausted through the conduit which is now in communication with a. chamber 98 on the side of the diaphragm 88 opposite the chamber 86. From the chamber 94 the exhaust air is transmitted through an exhaust passage 95 which extends longitudinally from the righthand end of the plunger 66 to a lateral portion which is registered with the adjacent end of an exhaust conduit 96 to atmosphere communicating through the wall of the cylinder 65, it being noted that the left hand end of the plunger 66 then cuts oil the left hand end of the cylinder from the conduit 96. When the plunger is in the position shown in Figure '1, for effecting downward movement of the piston 56 of the motor 52, air from the lower end of the cylinder 56 of said motor is exhausted through the conduit 58, chamber 98 at the left end of the valve cylinder 64, and passage I00 between the reduced end portion 82 and the inner wall of cylinder 64, said passage I00 then communicating with the exhaust conduit 96. With the plunger 66 in the position shown in Figure 7 the passage 95 is out ofi from communication nected and a hollow valve casing I54 which is connected with the casing I52 adjacent. one end and extends transversely thereof. Within the casing I54 are spaced. partitions I56 and I58 which divide the casing I54 into chambers I60 and I62 and I64. The partitions I56 and I58 have respective valve openings I63 and I65 therethrough controlled by movable valve members or closures I66 and I68 respectively, said valve members I66 and I68 being connected by a valve stem I10 of such length that when one of thevalves is closed the other of said valvesis open. Air under pressure is supplied to the chamber I60 through a conduit I12 connected with tank 12 by a pipe I13 and pipe H, and

an exhaust pipe I16 to atmosphere is connected with the chamber I66. It is to be noted that, if

desired, a pressure pump 290 may be interposed in the conduit I13. Valve members I66 andI68 are controlled by a solenoid I16 suitably mounted in a casing I11 attached to the casing I52. The solenoid is provided with a plunger I18 operably .connected to the valve stem I10 by means of a When the solenoid is energized the valves I66 and I66 are moved downwardly, as viewed in Figure 8, so that valve opening I63 is closed and valve opening I65 is opened. Air under pressure, supplied through conduit I12, enters chamber I60 passes through the opening I65 in the partition I58, into chamber I62, thence into the casing I52 and to the chamber B6 of the valve 53 by way of pipe 85. Upon deenergization of the solenoid the valve opening I65 is closed and the valve opening I63 is opened whereupon the pres sure in chamber 86 of valve 53 is relieved, the excess air in chamber 86 being exhausted to atmosphere through conduit 85, casing I52, chamber I62, opening I63 in the partition I56, chamber I64, and the exhaust conduit I18.

The electrical system, best shown in Figure 9, comprises a switch, which is termed herein a distributor 200 and which has a plurality of contact points 202 and contact points 204 and 266 respectively, arranged in a circle and adapted to be contacted by the free end of a rotatable switch with respect to the foregoing contacts. The arm 208 is connected by a wire 2I2 with a source of electrical power which, as shown, is a battery, indicated generally at 2, although any other suitable source of electric power may be used.

Certain of the solenoid operated valves 53 are I connected by respective wires 2I6 with respective contacts 202 and are also connected to the battery 2I4 by a wire 2I8 and respective branch. wires 220. Contact with any one or the contacts 202 by the contact member 288 will effect energization of the respective solenoid with which said contact is connected, which in turn willeffect actuation of the valves I66 and I68 of the respective solenoid valves I50 controlling a reto the back of panel 212.

spective valve 53 which in turn controls the actuation of the respective motor 52 and orifice valve with which said motor is connected.

If desired, in order tohave a greater range of effective orifice openings, a plurality of orifices (two or more) may be opened for a test, a desirable arrangement of this character being shown in Figure 9 wherein the contacts 204 and 206 are connected with relays 222 and-224 by wires. 26 and 228 respectively, each relay having a connection 230 with a return wire 232 connected with the battery 2I4 for completion of the relay circuits. The relays 222 and 224 are'adapted to control respective switches 234 and 236. The switch 234 controls the flow of current through wires 238240 and 242-244, the wires 238 and 242 being connected to a wire 23I to the battery and the wires 240 and 244 are respectively connected with the solenoid of a. valve I50 so that when switch 234 is closed the solenoids of a plurality of said valves I50 are energized, there being two valves thus energized in the arrangement shown in the drawing. Switch 236 controls the fiowof current through wires 246-248, 250252, 254-256 and 258-260. The wires 246, 250, 254, and 258 areconnected with the wire 23I and wires 248, 252, 256 and 260 are respectively connected with the solenoid of a valve I 50' so that when switch 236 is closed-by relay 224 the solenoids of four valves I50 are energized for effecting opening of four orifices. Other numbers of valves may be thus controlled if desired as well as other combinations of valves and more relay switches may be incorporated in the system. It is to be 236 may include valves connected with some of the contacts 202 or they may be other valves not otherwise connected into the electrical system. Moreover there may be other combinations of valves controlled by the relays which combinations may be various and numerous. A plurality of vertical contacts 282 are shown although one is generally sufiicient. If desired the surplus points may be controls.

Means for indicating the flow of airthrough or the pressure differential across the various oriflces or combinations of orifices, comprises a gage which as shown is preferably an inclined manometer tube 210, Figures 4 and 10, of known type having the -usual connections which are well known in the art, said tube 210 being attached to panel 212. Mounted behind the panel and tube 210 is a drum 214 which is rotatable on a shaft 216, Figure 10, mounted in a frame 211attached A plurality of graduated scales 218 are secured to the dru 214 and are adapted to be used in conjunction with the manometer tube 210, each scale being calibrated to measure the air fiow through the respective orifices or combinations thereof, or the pressure is preferably limitedwto the recommended usable range for each orifice, and the orifice sizes are so selected that a slight overlap in the recomused to provide still other orifice 8 mended range or values or rates of fiow is provided for succeeding orifices.

In orderrto correlate the proper scales with the respectiveprifices or group of orifices for which they are calibrated the scale supporting drum 214, on which the various scales are mounted, is connected with the arm 208 of the distributor 200by shaft 216, the scale supporting drum 214 and the distributor being so constructed and arranged that there is a contact for each scale and when any particular scale is brought into position adjacent a manometer tube 210 and registration with slot 219 the arm 208 of the distributor will contact one of the contacts 202, 204 or 206.

When the conditions of flow of fluid'to the device to be tested changes wherebythe orifice then being used is no longer efficient for accurate measurement of the flow, the operator can change to another size orifice which will give accuracy and efficiency. To effect such a change the operator rotates the drum by means of a knurled wheel 280 secured to the shaft 216 and which is received in a slot therefor in the panel 212, the rim of said wheel 280 extending through said slot and projecting outwardly of the front face of the panel.

Operation Assuming that all the orifices are closed and that the first scale (the scale for the smallest orifice) is moved into position relative to the manometer tube 210, the arm 208 contacts the contact 202 for the bottom valve I as shown in Figure 9. The solenoid of the lower solenoid valve I50 is then energized whereupon the valve members I68 and I66 thereof are moved downwardly so that the opening I is opened and the opening I63 is closed by valve I66. Air under pressure then is transmitted through the valve I50 and conduit 85 to the chamber 86 of the valve 53. The pressure of the air in chamber 86 acts on the diaphragm 88 and effects movement to the left, as shown in Figure '1, of plunger 66. Compressed air from conduit 68 is transmitted to conduit 58, as hereinabove deorifice as above described, whereupon the lower solenoid operated valve I50 will be deenergized causing the valves I66 and I68 to return to their normal position which is shown in Figure 8. The pressure in chamber 86 of the lower. valve 53 will then drop to atmospheric pressure and spring 80 thereof will move the plunger to its normal position as shown in Figure 7. Air under pressure will then be transmitted from conduit 68 to conduit 60, of the lower valve 53, which leads to the upper end of the lower cylinder 54 whereupon the piston 56 thereof will be forced downwardly to bring the respective valve 40 into contact with the flange 26 thereby closing the As the scales are successfully brought into position relative to the manometer tube 210 the arm 208 contacts the respective contact points 202 thereby closing the respective circuits to the solenoids of other valves individually or to the respective scale, calibrated fora certain air flow,

permitted by the opening of a plurality of orifices, is brought into position relative to the manometer tube 210 the proper orifices are automatically opened. Thus it will be seen that the possibility of error in making tests'with the'.

present invention is nullified or entirely eliminated.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and though said invention has been illustratedin connection with but one modification thereof it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinabove described being merely a preferred embodiment.

We claim: 7

1. In a de ice for measuring fluid flow: a conduit through which air is adapted to flow; a plurality of orifices through which the air is adapted to flow into the conduit, said orifices being of different sizes; valves controlling said orifices; means for indicating the flow of air through said orifices; a scale for each orifice calibrated for measuring the rate of flow therethrough; means adapted to bring the scale corresponding to the orifice in use into reading position adjacent the first mentioned means; means for opening the valves of. the respective orifices; and means for synchronizing the movement of the scales into position adjacent the indicator and the opening of the respective orifices.

2. The invention defined by claim 1 wherein the valves controlling the orifices are actuated by pneumatic means.

3. The invention defined the scale positioning mechanism controls electrical means for selecting the orifice valve to be opened.

4. The invention defined by claim 1 wherein there is an electrical system controlling the valve opening means and including a distributor; and

means connecting the scale mechanism and distributor whereby positioning a scale will automatically effect opening of the orifice for which said scale is calibrated.

5. The invention defined by claim 1 including means for automatically efiecting opening the valves of a plurality of orifices; and wherein there is a scale graduated to measure the air flow through said plurality of orifices.

6. In a device formeasuring fluid flow: a conduit through which air is adapted to flow; a-

plurality of orifices through which the flowing air is adapted to pass into the conduit, said orifices being of various sizes; a valve for each orifice; a pneumatic system including a pneumatic motor for each valve for moving same to open position and for closing same; pneumatic valve means adapted to control the respective motors; means for indicating the flow of air through the orifices; a graduated scale for each orifice and calibrated according to the size thereof, said scales being by claim 1 wherein.

adapted to be selectively positioned adjacent the indicating means; and automatic means so constructed and arranged that when a scale is brought into position adjacent the indicating means the valve of the orifice for which the scale is calibrated is automatically opened, all other valves being closed.

7. In a device for measuring fluid flow: a passage through which air is adapted to flow; a

plurality of orifices of varioussizes communicating with said. passage and through which the flowing air is adapted to pass; a valve controlling each orifice; means for indicating the flow of air through the orifices; a scale for each orifice calibrated to measure the flow therethrough and adapted to be selectively positioned adjacent the indicating means; means for opening and closing the respective valves of the orifices; and electrical control means synchronized with the positioning movement of said scales, said electrical means being so constructed and arranged that the positioning of a scale adjacent the indicating means will automatically efiect opening of the orifice for which said scale is calibrated.

8. In a device for measuring fluid flow: an air passage through which air is adapted to flow; a plurality of orifices of various sizes in the passage air stream; a valve for each orifice; pneumatic means for controlling the respective valves; means for indicating the flow of air-through the orifices; a scale for each orifice adapted to measure the flow of air through said orifice; means for positioning the respective scales adjacent the flow indicating means; and electrical means controlled by the scale positioning means and so constructed and arranged as to control the pneumatic means for opening the valve of the orifice for which the scale is calibrated.

9. The invention defined by claim 8 wherein the electrical means includes means for opening the valves of a, plurality of orifices, and said scale is calibrated to measure the flow of air through said plurality of orifices.

10. The invention defined by claim 8 wherein the pneumatic system includes a pneumatic motor for each orifice valve so constructed and arranged as to open and close said valve; and a control valve for each motor adapted to control the flow of air thereto whereby the motor respectively opens and closes said orifice valve.

11. The invention defined by claim 8 wherein the electrical system includes a distributor actuated by the scale positioning means; and electrically actuated means for each pneumatic valve adapted to control same.

12. The invention defined by claim 8 wherein the pneumatic means includes a pneumatic motor for each orifice valve which is adapted to open and close said valve; a pneumatic control valve for each motor adapted to control the flow of air thereto; a second pneumatic valve adapted to control the first mentioned pneumatic control valve; a distributor for the electrical system, said distributor being controlled ,by the scale positioning means and includes'a plurality of contact points; and a solenoid for each of the second mentioned pneumatic valves for controlling the same, the solenoids being connected to respective contacts of the distributor.

13. In a device for measuring fluid flow: an air passage through which air is adapted to flow; a plurality of orifices in the path of the air flow; an orifice valve for each orifice; pneumatic motors for respective orifice valve-s; pneumatic control valves for controlling the flow of therethrough; means for positioning the respec-' tive scales adjacent the indicating means; and means connecting the scale positioning means and distributor arm whereby said arm is adapted to contact respective contact points and energize a solenoid for efiecting opening of the valve of the orificefor which the scale is calibrated, when such a scale is positioned adjacent'the air fiow indicating means.

14. The invention defined by claim 13 includ ing a relay connected to a contact point of the distributor; a switch actuated by said relay; electrical circuits controlled by said switch whereby a plurality of solenoids are energized for effecting the opening of a plurality of orifice valves, there being a scale calibrated to indicate the air fiow through the opened orifices.

15. In a device for measuring fiuid flow: a conduit through which fluid is adapted to flow; a plurality of orifices of different sizes communicating with said conduit and through which fluid is adapted to fiow; means ,for measuring the fluid fiow including an indicator and a calibrated scale for each orifice; means adapted to bring the scale corresponding to the orifice in vuse into reading position with the indicator; means for rendering the respective orifices operative; and means for synchronizing the positioning of the respective scales into reading position with the indicator and rendering operative the respective orifices for which said scales are calibrated.

16. In a device for measuring ,the characteristics of a charge forming device for internal combustion engines or the like: an air passage through which air is adapted to flow; a plurality of orifices in the passage air stream; a valve for each orifice; means for controlling the respective valves; means for indicating, the flow of air through the orifices; a scale adapted to measure the fiow of air through one of said orifices; a scale adapted to measure the flow of air through a plurality of said orifices; means for positioning the respective scales adjacentthe flow .indicating means; and means controlled by the scale positioning means, so constructed and arranged as to control the valve opening means and syn-' chronize the opening of the valves of the orifices with the positioning of the respective scales for which said orifices are calibrated.

17. In a device for measuring the characteris tics of a charge forming device for internal combustion engines or the like; an air passage; a plurality of orifices of various sizes connected with said passage; a valve for each orifice; means for I scales adjacent the flow indicating means; and

means controlled by the scale positioning means and so constructed and arranged as tocontr'ol the opening of the valves of the respective combinations of orifices in accordance with the posi- L. E. CROSBY. CHARLES W.

Certificate of Correction Patent No. 2,414,582. January 21, 1947.

LAWRENCE E. CROSBY ET AL.

It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 4, line 39, after orifice insert valve; column 12, line 38, claim 17, after said insert the words and period combinations are calibrated; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 26th day of October, A. D. 1948.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

